Process of drying molds for casting pipes and apparatus therefor



2 Sheets'-Sh'eet 1.

Patented Jul 12, 71881;

(No Model.)

J. K. DIMMIGK. PROGESS or DRYINGMOLDS FORUASTING PIPES AND APPARATUS THEREFOR.

Fig.1;

N. PETERS Photo-Lithographer: Waxhingkun. D. Q

(No Model.) 2 Sheets-Sheet 2.

J. KQDIMMIGK. PROCESS OF DRYING MOLDS FOR CASTING PIPES AND APPARATUS,

v S THEREFOR. r S No. 244,199. Patented July 12,1881.

J11 if iDJ E J 17 J A v 76 v Z1 z 7 'e11 0/ 01 e ,4 H W I UNITED STATES PATENT OFFICE.

JACOB K. DIMMICK, OF NEWPORT, KENTUCKY.

PROCESS OF DRYING MOLDS FOR CASTING PIPES AND APPARATUS THEREFOR.

SPECIFICATION forming part of Letters Patent No. 244,199, dated July 12, 1881,

Application filed May 24, 1881. (No model.)

To all whom it may concern:

Be it known that I, JACOB K. DIMMICK, of Newport, in the county of Campbell and State of Kentucky, have invented certain new and useful Improvements in the Process of Drying Molds for Casting Pipes, and the Apparatus Used therefor; and I do hereby declare the following to be a full, clear, and exact description of the same.

In the drawings, Figure 1 is a transverse section through the furnace and pit wherein the molds are dried, the section being taken in the line :20 a", Fig. 3. Fig. 2 is a partial plan view and a section taken in the line y y, Fig. 1. Fig. 3 is a vertical section of the same, taken in the line z 2, Fig. 1. Fig. 1 is an enlarged sectional view of the floor and one of the plates for adjusting the size of the flues through which the heat is discharged from the furnace into the molds to be dried. Fig. 5 is an enlarged plan view of a portion of the floor. Fig. 6 shows, in perspective, the upper and lower side of one of the reducing-plates. Figs. 7 and 8 respectively are enlarged vertical sections through the lower end of the mold and the adjustable plates, showing the latterin reverse positions. Fig. 9 is a plan of a ring used for vertical adjustment of the rolls.

Similar letters of reference denote like parts in the several figures of the drawings.

The object of my invention is to improve the process and apparatus used for drying the molds in which water, gas, and other pipes are cast, and thereby to edect a saving in labor, time, and fuel,while enabling the process of molding, drying, and casting to be carried on continuously. The usual method of molding these pipes is to form the mold in a long castiron flask divided longitudinally and having thetwo parts hinged together on one side,while the opposite joint is fastened by-a suitable catch, which can be disengaged to open the flask and allow its contents to be discharged after the pipe has been cast. In order to dry the mold thus formed, a series of flasks containing the molds are placed upright within a closed pit or oven immediately over afurnace, and the heat from the furnace caused to circulate among them until themolds are thoroughly dried. It is essential that the inner face of the molds shall be completely dried before the molten iron is poured into them; otherwise the steam formed by the contact of the hot iron with the damp inner surface of the molds will either cause an explosion, and thus destroy the mold, or will leave the surface of the casting honey-combed, and thereby render it defective and unsalable. It is also apparent that when the heat is applied to the flasks externally it must penetrate completely through them before reaching the molds, and must also penetrate completely inward through the molds in order to reach the inner surface of the latter anddryit. Theheatnecessaryforthispurpose necessitates the consumption of a large quantity of fuel, and must be continued many hours, itrequiring to dry the molds thoroughly by this method about twelve hours. It has therefore been the practice to make as many molds as the pit would hold, requiring one day for the purpose, and then to dry them out duringthe night, to have them ready for casting the next mornin g. The heat is not by this process applied with any degree of regularity, because, as a part passes through the molds and a larger part around the flasks, some of the molds will be heated much more than others, according to their location relative to the fire, and the re sult is that a part is burned-that is to say, the carbon composing the blackwash with which the face of the molds is treatedis burned off-or else some of the molds are not thoroughly dried, frequently both conditions being found in one pit. There is also a great waste of heat and fuel, and a marked delay, from the fact that most of the heat has to penetrate both the flask and the entire thickness of the mold before reaching the inner surface of the mold, upon which alone it is needed. It is onlynecessary to dry the inside of the mold to a very slight depthsay one-sixteenth of an inch-- and all the heat expended on the remainder of the mold and upon the flask is wasted. When the molten'iron is poured into the molds the heat gradually dries them in an outward direction and causes the vapor to escape outwardly through the vent-holes of the flask. Efforts have been made to apply the heat directly to the inside of the molds for the pur pose of drying them outward from the center, but have been practical failures by reason of .the fact that the blast of heat or flame would be so intense where it entered the flask as to burn the blackwash, while not sufficiently drying the remoter interior surface of the mold.

To obtain the advantages of rapid, continuous, and uniform drying of the inner surface or skin of the mold by the direct application of the heat and products of combustion from the furnace to the interior of the mold, and at the same time provide against the burning of I the blackwash where the heat enters the mold without waste of heat, is one of the most important objects of my invention.

Referring to the accompanying drawings, A A represent two brick furnaces, preferably built 'below the surface of the ground, each having a short grate-surface, B, at the front end, an arch, 0, above the grate and extending the whole length of the furnace, and afloor, D, of iron or other suitable material, supported above thearches by girders E, The spaces between the arches and floor are preferably filled withsand or other proper material, for the purpose of keeping the floor cooland to prevent it and the girders from bcing warped by the heat. The front ,of the furnace, above the ash-pit, is closed in any suitable manner, and provided with a door or doors for the introduction of coke, which is the fuel preferablyemployed for drying molds. Ihaye shown two furnaces in the drawings; hutone orany other number may be used, depending upon the capacity of the pipe-works. L y

B is a pit, into which the furnace or the fire therefrom may be extended, if desired.

The floor D, at regular distances, is formed with openings G, which communicate with the interior of the furnacethrough brick or other flues H, preferably opening through the arches. These flues form chimneys to directthe heated air and products of combustion fromthefurnace directly into the molds withinthe flasks I, which are placed in an upright position over the openings in the floor, as shown in Fig.3, as many moldsbeing placed inthe pit as desired. The orifice by which the flue communicates with the in terior of the flask is made of much less diameter than the interior offthe mold, and arranged concentric withthe mold, or substantially so. The flask is supported above the floor of the furnace; by ribs or supports J, so as to allow cool airfromwlthout to enter around the discharge-orifice of the flue. Iextend theflue or flue-plate through which the blast fromthe furnace is admitted to the mold at least as high as the mouthof the mold, or slightly higher, so that there may be no waste or spreading of the heat, and so as toinsure proper suction of the cool air around it, while .this flue or flue-plateshould be at its mouth so much smaller in external diameter than the mouth of the mold as to insure sufficient space for the cool air to pass between it and the inner wall of themold. By this arrangement I carry the flame and heat without loss directly into the mold, while. by reason of the orifice through which it en ters being separated from the inner wall of the mold by a broad lateral ring, and of the open space for the entrance of cool air around it, I effectually guard against such contact of the flame and intense heat with the walls of the mold at and near its lower end as would burn the blackwash or causeflother injury, and insure a substantially even application of the heat throughout. The ascending current of heat and flame produces a draft, which draws the cool air through the space, beneath the mold and around the orifice of the flue or fluevplate, causing a constantly-ascending current of cool air to envelop and form a kind of sheath about the current of flame and intense heat at the pointwhere it enters the mold, thus modifying itseft'ects at this point. As: it rises in the mold this sheath or shield of cool air. grad' ually losesits eifect as such, as the occasion for it disappears, whilev the ascending comps of hot air and products of combustion becomes more direct in its application asit becomes more remote. Its effect is therefore distributed with substantial uniformity throughout the length of the mold,and a continuously rapid, even, andeconomical drying ofthe inner surface of the mold obtained without danger of insufiicient heating at any point. As it is only necessary to dry the inner wall of the mold to a depth of, say, one-sixteenth of an inch, a small amount ofheat serves for. the purpose when thus applied and distributed. The flasksare not heated snfliciently tointerfere with their being conveniently, handled at once, and the time lost inwaitingforthemlto cool when heated by the method hitherto commonly usedis areda,

e c l-a r s es mayb ma e in an riety of ways, thatwhich I'prefer being to supportthe flasksabovethe floor by short blocks or strips J, placettat intervals faround each chimney, as shown inFigs. 5 and 6, so that the air can e t rthe; m 12lbebi hem. i su cient quantities, its course being indicated by the r s..i ?is--.3, 1 i I r It is important hat this furnace beisofconstr t as ter mo o fl'er h s, hi s saving the expense of constructing furnaces or floors foreachsize. I therefore make the fluesand holesin the floor D of sufiicients'ize to accommodate the largest molds capablefof being dried in such a furnace, and then reguat th s ze and posit o t e n yst versible reducing-plates set into or over them, as shown in Figs. 3, 4, 5, 6, 7, and 8., -v Iffthe mold is of small diameter, the reducing-plate is applied to coventhe flue, such plate being formed with an opening near one 'end. (,This reduces the exit of the flue. andcarriessnch e itne rern 'thaat w n T 11 0 is then centered over, the exit, an d'as it is of such small diameter as not to surround the re ducingplate it rests upon the sidestrip, J,Iand the end stripnearest the exit; or a small block or strip corresponding to strip J may be placed on the plate, as shown in Fig. 6, to furnish a fourth support. If a large mold is to be dried, then the reducing-plate is reversed, so as to carry the exit farther away from the wall of the pit, and the mold centered over the exit, resting upon the four supporting-strips J. By means of the large flues and reversible reducing-plates the position of the exits is changed to center the heat within molds of different diameters. The plates may be made to set into the holes in the floor, or in the form of simple covers resting upon the floor; but, however made, care must be taken not to close the air-induction passages under the lower end of the molds above the floor. The crown of these plates, in which the orifice is formed, is sufficiently raised to project into the mouth of the flask, thus bringing this orifice slightly above the base of the ascending column of cool air, which is sucked in around it.

In a furnace of this kind it is desirable that the molds shall be placed as near each other as practicable. The flare of the upper end of the flask will, where they are all upon the same level and of the same length, necessitate allowing for each mold at least the entire diameter of the flask at the point of its greatest flare. If these flares are brought to difi'erent levels, they can be allowed to project respectively over and under those adjacent to them, and much space and consequent advantage in the utilization of the heat of the furnace saved. For this purpose I provide rings or supports M, (shown in Figs. 3, 7, and 9,) which may at will be placed under alternate flasks to raise them, so that their point of greatest diameter will be caused to project over the corresponding parts of those adjacent to them.

Suitable guides may also be arranged on the floor D, or reducingplates, in any convenient manner for setting the flasks properly over the chimneys or over the fire-holesin the plates. In some cases the holes in the floor are of the proper size to receive the molds without the use of the plates, and the guides may then be fastened to the floor. Such holes or chimneys as are not used may be closed by caps, as shown in Fig. 3, or by any other suitable device.

When the molds are being dried I place an iron cover, L, on the top of'the flask, of such size as shall leave an exit around or through it about equal to or smaller than the air-induction at the bottom of the flask, for the purpose of preventing the air from drawing too rapidly through the mold. As shown in Fig. 3, the cover is made with a central aperture; but it may be perforated or otherwise formed to accomplish the object, or its air-exit may be made adjustable in any proper manner.

I claim as my invention- 1. The process of drying the molds for easting, consisting in directing the heat into the interior of the molds, in connection with a current of cool air enveloping the jet of hot air where it enters the mold, and serving to protect the same.

2. The process of drying molds, consisting in conveying the heat from the furnace upward directly into the interior of the molds, in connection with a current of cooler air interposed between the current of heat where it enters the inner wall of the mold and said inner wall.

3. An improvement in the art of drying pipe-molds, consisting in directing the heat into the molds from a fire at the bottom of said molds, while protecting the inner walls of the molds at and near the place where the.

current of heat enters by a sheath of cool air drawn into the mold by the suction created by the current of heat.

4. An improvement in the art of drying the inner surface of molds, consisting in conducting a current of heat from the furnace di' rectly into the mold, discharging it therein through an orifice of smaller diameter than the mold, and thence passing it through the mold, while protecting the wall of the mold nearest to said orifice from burning by means of a sheath of cool air drawn between said wall and said orifice by the draft created by the heated current.

5. The process of drying molds, consisting in conducting the products of combustion from the furnace directly into the mold, in a jet so confined that it cannot come in contact with the mold at the place of entrance, and further shielding the mold at the place of entrance from the violence of the flame by a constant current of cool air from without, caused to ascle for the flasks containing the molds, a perforated floor to support the flasks, a series of flues or chimneys to direct the fire from the furnace through the floor and into the molds, a series of supports or strips around each .flue above the floor, and a series of reversible reducing-plates for the flues, substantially as described, for the purpose specified.

S. In combination with the fines of the fu1= nace communicating directly with the interior of the mold resting vertically above said flues, a ring or support for the purpose of adjusting the adjacent flasks at different heights, and thus economizing space, as described.

JACOB K. DIMMIOK, Witnesses:

JOHN OELERING, DANL. KELLY. 

